code: def _scalar_func_3(self, s):
      self.fcount += 1
      p = -np.sin(10 * s)
      dp = -10 * np.cos(10 * s)
      return p, dp
  
imports: from __future__ import division, print_function, absolute_import
  from numpy.testing import assert_, assert_equal, assert_array_almost_equal, assert_array_almost_equal_nulp, assert_warns
  from scipy._lib._numpy_compat import suppress_warnings
  import scipy.optimize.linesearch
  from scipy.optimize.linesearch import LineSearchWarning
  import numpy
label_desc: Use image node_id 3 for calling the TestLineSearch obj's underlying member method code with example usage: obj._scalar_func_3(s) and returns: p,  dp